1. Field of the Invention
The invention relates to an ultra wideband antenna with band-notched characteristics, particularly to an ultra wideband antenna capable of suppressing transmission and reception in a particular frequency range through providing two complementary, separate, circular resonators, connected with each other, in a signal feeding unit.
2. Description of Related Art
Accompanied by rapid growth of demand of radio transmission over a short distance, wireless communication of local area networks and variety of personal mobile communication products, the quantity and speed of transmission of radio communication data are increasing. In view of that, in February, 2002, the Federal Communications Commission approved that ultra wideband technology may be used in a general commercial communication system, and regulates that ultra wideband communication is a high transmission, low power and short distance communication system. However, the frequency range of the ultra wideband (from 3.1 GHz to 10.6 GHz) includes the frequency band, such as 5.150 GHz to 5.875 GHz, used in a wireless local area network (WLAN). Thus, interference of the communication signals between the ultra wideband communication and the WLAM system will be incurred.
Therefore, in order to allow the ultra wideband communication to become more practicable, those engaged in the industry submit many solutions to suppress signals transmitted or received in the operation frequency band of the WLAN for the ultra wideband communication, so as to reduce the afore-mentioned signal interference. As described below, there are three conventional ultra wideband antennas with band-notched characteristics that are able not to transmit or receive a high frequency signal in the operation frequency band (5 GHz to 6 GHz) of the WLAN.
As shown in FIG. 1A, the first conventional ultra wideband antenna with band-notched characteristics includes a substrate 11, a grounding unit 12, a signal feeding unit 13, and a rectangular strip slot 14. The substrate 11 is preferably a microwave substrate with FR-4 material. The grounding unit 12 is installed on the substrate 11 and scooped with a first slot 121 and a first strip hole 122, in which the first strip hole 122 is communicated with the first slot 121 and extended to a side 111 of the substrate 11. In addition, the signal feeding unit 13 is installed on the substrate 11 and includes a horizontal portion 131 and a vertical portion 132, in which the horizontal portion 131 is in the first slot 121 and the vertical portion 132 is in the first strip hole 122.
As shown in FIGS. 1A and 1B, the first slot 121 of the grounding unit 12 is a rectangular strip slot and the shape of the horizontal portion 131 of the signal feeding unit 13 is rectangular. Further, the material of the grounding unit 12 and the signal feeding unit 13 is metal. Furthermore, the rectangular strip slot 14 is installed on the horizontal portion 131 of the signal feeding unit 13 and has an opening 141, in which the direction of the opening of the rectangular strip slot 14 is parallel to the extension direction of the vertical portion 132 of the signal feeding unit 13 and the length of the rectangular strip slot 14 is 21.4 mm.
Besides, the sizes of various labels for the first conventional ultra wideband antenna with band-notched characteristics as shown in FIGS. 1A and 1B are listed in the following Table 1:
TABLE 1labelsize (mm)labelsize (mm)labelsize (mm)L35W33Ls23Ws13t2Sf0.4Wf3.6AB10.8AE4
Therefore, in the first conventional ultra wideband antenna with band-notched characteristics, the “band-notched unit” is constituted by the rectangular strip slot 14 such that the first conventional ultra wideband antenna with band-notched characteristics is able not to transmit or receive a high frequency signal in the frequency range from 5 GHz to 6 GHz. The detailed characteristic curves, such as return loss and gain, will be shown together with those of the present invention in the following.
As shown in FIG. 2A, the second conventional ultra wideband antenna with band-notched characteristics includes a substrate 21, a grounding unit 22, a signal feeding unit 23, and a complementary, separate, circular resonator 24. The substrate 21 is preferably a microwave substrate with FR-4 material. The grounding unit 22 is installed on the substrate 21 and scooped with a first slot 221 and a first strip hole 222, in which the first strip hole 222 is communicated with the first slot 221 and extended to a side 211 of the substrate 21. In addition, the signal feeding unit 23 is installed on the substrate 21 and includes a horizontal portion 231 and a vertical portion 232, in which the horizontal portion 231 is in the first slot 221 and the vertical portion 232 is in the first strip hole 222.
As shown in FIGS. 2A and 2B, the first slot 221 of the grounding unit 22 is a rectangular slot and the shape of the horizontal portion 231 of the signal feeding unit 23 is rectangular. Further, the material of the grounding unit 22 and the signal feeding unit 23 is metal. Furthermore, the complementary, separate, circular resonator 24 is installed on the horizontal portion 231 of the signal feeding unit 23 and includes a first rectangular strip slot 241 and a second rectangular strip slot 242, in which the first rectangular strip slot 241 surrounds the second rectangular strip slot 242. The first rectangular strip slot 241 and the second rectangular strip slot 242 respectively have an opening 243 and an opening 244 and the direction of the opening of the first rectangular strip slot 241 is opposite to the direction of the opening of the second rectangular strip slot 242. Furthermore, the direction of the opening of the first rectangular strip slot 241 is parallel to the extension direction of the vertical portion 232 of the signal feeding unit 23.
Besides, the sizes of various labels for the second conventional ultra wideband antenna with band-notched characteristics as shown in FIGS. 2A and 2B are listed in the following Table 2:
TABLE 2labelSize (mm)labelsize (mm)labelsize (mm)L35W33Ls23Ws13t2Sf0.4Wf3.6AB10.8AE4g0.1c0.2d0.4r0.9
Therefore, in the second conventional ultra wideband antenna with band-notched characteristics, the “band-notched unit” is constituted by the complementary, separate, circular resonator 24 such that the second conventional ultra wideband antenna with band-notched characteristics is able not to transmit or receive a high frequency signal in the frequency range from 5 GHz to 6 GHz. The detailed characteristic curves, such as return loss and gain, will be shown together with those of the present invention in the following.
As shown in FIG. 3A, the third conventional ultra wideband antenna with band-notched characteristics includes a substrate 31, a grounding unit 32, a signal feeding unit 33, a first complementary, separate, circular resonator 34 and a second complementary, separate, circular resonator 35. The substrate 31 is preferably a microwave substrate with FR-4 material. The grounding unit 32 is installed on the substrate 31 and scooped with a first slot 321 and a first strip hole 322, in which the first strip hole 322 is communicated with the first slot 321 and extended to a side 311 of the substrate 31. In addition, the signal feeding unit 33 is also installed on the substrate 31 and includes a horizontal portion 331 and a vertical portion 332, in which the horizontal portion 331 is in the first slot 321 and the vertical portion 332 is in the first strip hole 322.
As shown in FIGS. 3A and 3B, the first slot 321 of the grounding unit 32 is a rectangular slot and the shape of the horizontal portion 331 of the signal feeding unit 33 is rectangular. Further, the material of the grounding unit 32 and the signal feeding unit 33 is metal. Furthermore, the first complementary, separate, circular resonator 34 and the second complementary, separate, circular resonator 35 are installed on the horizontal portion 331 of the signal feeding unit 33, and the first complementary, separate, circular resonator 34 and the second complementary, separate, circular resonator 35 are spaced apart from a distance S in installation.
As shown in FIG. 3B, the first complementary, separate, circular resonator 34 includes a first rectangular strip slot 341 and a second rectangular strip slot 342, in which the first rectangular strip slot 341 surrounds the second rectangular strip slot 342. The first rectangular strip slot 341 and the second rectangular strip slot 342 respectively have an opening 343 and an opening 344 and the direction of the opening of the first rectangular strip slot 341 is opposite to the direction of the opening of the second rectangular strip slot 342. Furthermore, the direction of the opening of the first rectangular strip slot 341 is parallel to the extension direction of the vertical portion 332 of the signal feeding unit 33. In addition, the second complementary, separate, circular resonator 35 includes a third rectangular strip slot 351 and a fourth rectangular strip slot 352, in which the third rectangular strip slot 351 surrounds the fourth rectangular strip slot 352. The third rectangular strip slot 351 and the fourth rectangular strip slot 352 respectively have an opening 353 and an opening 354 and the direction of the opening of the third rectangular strip slot 351 is opposite to the direction of the opening of the fourth rectangular strip slot 352. Furthermore, the direction of the opening of the first rectangular strip slot 341 is parallel to the direction of the opening of the third rectangular strip slot 351.
Besides, the sizes of various labels for the third conventional ultra wideband antenna with band-notched characteristics as shown in FIGS. 3A and 3B are listed in the following Table 3:
TABLE 3labelSize (mm)labelsize (mm)labelsize (mm)L35W33Ls23Ws13t2Sf0.4Wf3.6AB10.8AE4g0.1c0.2d0.4r0.9S0.2
Therefore, in the third conventional ultra wideband antenna with band-notched characteristics, the “band-notched unit” is constituted by that the first complementary, separate, circular resonator 34 and the second complementary, separate, circular resonator 35 are spaced apart from a distance S in installation, such that the third conventional ultra wideband antenna with band-notched characteristics is able not to transmit or receive a high frequency signal in the frequency range from 5 GHz to 6 GHz. The detailed characteristic curves, such as return loss and gain, will be shown together with those of the present invention in the following.
As described above, in the three conventional ultra wideband antennas with band-notched characteristics, either the suppression ability of the “band-notched unit” is insufficient, or the “band-notched unit” occupies a big area of the substrate. Therefore, it is necessary in the industry to have an ultra wideband antenna with band-notched characteristics, having better suppression ability and occupying a smaller substrate area.